Objectives: Group-randomized designs are well suited for studies of professional development because they can accommodate programs that are delivered to intact groups (e.g., schools), the collaborative nature of professional development, and extant teacher/school assignments. Though group designs may be theoretically favorable, prior evidence has…

Active parental consent policies have been blamed for low participation rates and selection bias (i.e., loss of "high-risk" youths) in school-based studies. In this article, the authors describe active consent procedures that produced an overall active consent rate of 79% in a sample of more than 4,500 middle school students attending 29…